Better determine if ICC colorspaces can be used for blending.

Implement CPDF_ColorSpace::IsNormal() and check it when rendering. While
IsNormal() is trivial for most colorspaces, it needs to be implemented
separately for ICC colorspaces.

This fixes a rendering regression from commit 1c0de38c.

BUG=chromium:847346

Change-Id: Iaafed3f8ee40b26ac2cbfbdf2251407f7935311b
Reviewed-on: https://pdfium-review.googlesource.com/36571
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

3 files changed, 24 insertions, 5 deletions

diff --git a/core/fpdfapi/page/cpdf_colorspace.cpp b/core/fpdfapi/page/cpdf_colorspace.cpp
index cf1f25063f..b78fe9acfc 100644
--- a/core/fpdfapi/page/cpdf_colorspace.cpp
+++ b/core/fpdfapi/page/cpdf_colorspace.cpp
@@ -207,8 +207,7 @@ class CPDF_ICCBasedCS : public CPDF_ColorSpace {
                           int image_width,
                           int image_height,
                           bool bTransMask) const override;
-
-  bool IsSRGB() const { return m_pProfile->IsSRGB(); }
+  bool IsNormal() const override;
 
  private:
   // If no valid ICC profile or using sRGB, try looking for an alternate.
@@ -595,6 +594,12 @@ void CPDF_ColorSpace::EnableStdConversion(bool bEnabled) {
     m_dwStdConversion--;
 }
 
+bool CPDF_ColorSpace::IsNormal() const {
+  return GetFamily() == PDFCS_DEVICEGRAY || GetFamily() == PDFCS_DEVICERGB ||
+         GetFamily() == PDFCS_DEVICECMYK || GetFamily() == PDFCS_CALGRAY ||
+         GetFamily() == PDFCS_CALRGB;
+}
+
 CPDF_PatternCS* CPDF_ColorSpace::AsPatternCS() {
   NOTREACHED();
   return nullptr;
@@ -909,7 +914,7 @@ bool CPDF_ICCBasedCS::GetRGB(const float* pBuf,
                              float* G,
                              float* B) const {
   ASSERT(m_pProfile);
-  if (IsSRGB()) {
+  if (m_pProfile->IsSRGB()) {
     *R = pBuf[0];
     *G = pBuf[1];
     *B = pBuf[2];
@@ -947,7 +952,7 @@ void CPDF_ICCBasedCS::TranslateImageLine(uint8_t* pDestBuf,
                                          int image_width,
                                          int image_height,
                                          bool bTransMask) const {
-  if (IsSRGB()) {
+  if (m_pProfile->IsSRGB()) {
     ReverseRGB(pDestBuf, pSrcBuf, pixels);
     return;
   }
@@ -1010,6 +1015,16 @@ void CPDF_ICCBasedCS::TranslateImageLine(uint8_t* pDestBuf,
   }
 }
 
+bool CPDF_ICCBasedCS::IsNormal() const {
+  if (m_pProfile->IsSRGB())
+    return true;
+  if (m_pProfile->transform())
+    return m_pProfile->transform()->m_bNormal;
+  if (m_pAlterCS)
+    return m_pAlterCS->IsNormal();
+  return false;
+}
+
 bool CPDF_ICCBasedCS::FindAlternateProfile(
     CPDF_Document* pDoc,
     const CPDF_Dictionary* pDict,
diff --git a/core/fpdfapi/page/cpdf_colorspace.h b/core/fpdfapi/page/cpdf_colorspace.h
index fba63917f7..1789e21c58 100644
--- a/core/fpdfapi/page/cpdf_colorspace.h
+++ b/core/fpdfapi/page/cpdf_colorspace.h
@@ -85,6 +85,8 @@ class CPDF_ColorSpace {
                                   bool bTransMask) const;
   virtual void EnableStdConversion(bool bEnabled);
 
+  virtual bool IsNormal() const;
+
   // Only call these 3 methods below if GetFamily() returns |PDFCS_PATTERN|.
 
   // Returns |this| as a CPDF_PatternCS* if |this| is a pattern.
diff --git a/core/fpdfapi/render/cpdf_renderstatus.cpp b/core/fpdfapi/render/cpdf_renderstatus.cpp
index 8b58295ab4..29a30157df 100644
--- a/core/fpdfapi/render/cpdf_renderstatus.cpp
+++ b/core/fpdfapi/render/cpdf_renderstatus.cpp
@@ -2638,8 +2638,10 @@ FX_ARGB CPDF_RenderStatus::GetBackColor(const CPDF_Dictionary* pSMaskDict,
     return kDefaultColor;
 
   int family = pCS->GetFamily();
-  if (family == PDFCS_LAB || family == PDFCS_ICCBASED || pCS->IsSpecial())
+  if (family == PDFCS_LAB || pCS->IsSpecial() ||
+      (family == PDFCS_ICCBASED && !pCS->IsNormal())) {
     return kDefaultColor;
+  }
 
   // Store Color Space Family to use in CPDF_RenderStatus::Initialize().
   *pCSFamily = family;